I was reading Jason Boche’s blog on snapshots yesterday and noticed a misunderstanding. I tweeted Jason about this and his blog was updated in a sec. But I thought it might be handy to actually outline the basics again especially because during the VMTN Experts Podcast there was a huge discussion on snapshots. Unfortunately I could not join the call via audio so I decided to respond here. [Read more…] about Snapshots, the revision
snapshots
Defraging a VMDK
Team Fusion wrote a great post on “defragging” vm’s and why you shouldn’t do it. Or at least be very careful about it. Make sure to read it!
Before we begin, it’s important to note that defragmentation isn’t a necessary task – your virtual machine will still work just fine even if you never defrag, and the effects of fragmentation are usually not noticeable. Personally, I’ve never feel the need to defrag. However, if for some reason you do feel the need to defrag, here’s how to do it. Note that snapshots get in the way of proper defragmenting.
VSS Snapshots
If you just upgraded to 3.5 Update 2 and updated VMware tools and want to use VSS for snapshotting than you will have to enable this manually for each VM:
- In the VMware Tools installer, select Modify > Drivers > VSS.
- Complete the installation process.
- Restart the virtual machine to make sure VSS components are installed and running.
Checking for snapshots, html email report!
When reading the VMTN forum I stumbled upon a topic about checking the VMFS for snapshots. Besides snaphunter by Xtravirt, which is an excellent script, there isn’t much out there. You can check the VirtualCenter database for snapshots but this way you would not notice the orphaned snapshots. (Orphaned snapshot occur when the vmsd file gets corrupted.) A couple of months before Xtravirt posted their script I wrote my own snapshot checking script named snapcheck.sh. [Read more…] about Checking for snapshots, html email report!
Undocumented VCB config.js feature
One of my customers wanted to use the default VCB framework but did not want to quiesce the VM for several reasons. (Databases, Active Directory etc.) I could not find an option in the config.js file but noticed the following in the file glue.js:
// A fallback to be able to switch to non-quiesced snapshots
if (typeof(NO_QUIESCE) != "undefined") {
cmd +="-Q 0 ";
}
In other words, setting the option “NO_QUIESCE” with no value in config.js results in the VM not being quiesced, default it will quiesce the VM! I added the following line to the config.js file to accomplish this:
NO_QUIESCE="";